A STUDY OF RELATIONSHIP BETWEEN SOUTHERN HEMISPHERE ANNULAR MODE AND RAINFALL VARIABILITY OVER THE MARITIME CONTINENT

• Main Author: BIRASTRI ( NIM : 22411005 ); Pembimbing : Dr. Tri Wahyu Hadi, WIRID
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/19683
• Institution: Institut Teknologi Bandung

This study is concerned with the relationship between Southern Hemisphere Annular Mode (SAM), which occurs in the southern high latitude regions, and the rainfall variability over the Maritime Continent. Analysis of the teleconnection has been carried out using Global Precipitation Climatology Centre (GPCC) Full Data Reanalysis Version 6.0 and SAM index computed from the Met Office Hadley Centre's mean sea level pressure (MSLP) data set (HadSLP2). Standardized precipitation index (SPI) and emprical orthogonal teleconnection (EOT) methods were also employed to analyze the data. It is found that, during the period of 1979 to 2004, the SAM-rainfall teleconnection is characterized by temporal and spatial variations. At seasonal time-scale, SAM+ events have stronger association with positive rainfall anomalies during Mar-Apr-May (MAM) and September-October-November (SON) periods, and negative rainfall anomalies in December-January-February (DJF). Further analysis also revealed that the response to SAM is more evenly distributed for the SON but there are noteable differences between eastern and western Maritime Continent for the MAM periods. At longer time-scale, the telconnection is affected by the trend in SAM index whose values tend to be more positive since the climatic shift year around 1976. Prior to climatic shift, the influence of SAM was limited to Australian region and has been extending northward to the tropics, including the Maritime Continent, and even further to the sub-tropics in the northern hemisphere. The teleconnection at interannual time-scale shows more complex patterns due to SAM-ENSO correlation but it is still clear that there is an independent interannual mode of SAM that affect rainfall in the Maritime Continent.